1. Field of the Invention
The present invention relates to a centrifugal air-oil separator disposed horizontally and including integrally a substantially cylindrical air-oil separation chamber and a substantially conical liquid discharge chamber.
2. Description of the Related Art
Centrifugal air-oil separators are already known to the public through, for example, JP-A-11-264312. A centrifugal air-oil separator disclosed in this Japanese Unexamined Patent Publication is designed to separate oil mist from blow-by gases of an engine and includes an upper air-oil separation chamber and a lower liquid discharge chamber which are disposed with their axes being oriented vertically. When blow-by gases containing oil mist is supplied into the interior of the cylindrical air-oil separation chamber which is situated at an upper position in a tangential direction, a swirl flow is generated, and oil mist separated radially outwardly by virtue of centrifugal force is discharged from a lower end of the conical liquid discharge chamber which is situated at a lower position, whereas the blow-by gases from which the oil mist was separated is discharged upwardly from the center of the air-oil separation chamber.
While the conventional centrifugal air-oil separator is vertically disposed with the axes of the air-oil separation chamber and the liquid discharge chamber being oriented vertically, there sometimes occurs a necessity to dispose the centrifugal air-oil separator horizontally due to the limitation to the mounting space. Even when this occurs, separated liquid must be discharged from the liquid discharge chamber in a smooth fashion.
The prevent invention was made in view of the situations and an object thereof is to enable the smooth discharge of separated liquid even in the event that the centrifugal air-oil separator is disposed horizontally.
With a view to attaining the object, according to a first aspect of the invention, there is provided a centrifugal air-oil separator including: a substantially cylindrical air-oil separation chamber and a substantially conical liquid discharge chamber which are integrated with each other and horizontally disposed; and an air-oil separation plate disposed between a gas supply port communicating with-the air-oil separation chamber and a gas discharge port communicating with the liquid discharge chamber, wherein a liquid discharge port is provided at a lowest portion between a largest-diameter portion of the liquid discharge chamber and the air-oil separation plate.
According to the construction, since the air-oil separation plate is disposed between the gas supply port communicating with the air-oil separation chamber and the gas discharge port communicating with the liquid discharge chamber, the liquid separation effect can be enhanced by generating a strong swirl flow within the air-oil separation chamber through prevention of short-circuiting between the gas supply port and the gas discharge port, and the reverse flow of liquid from the liquid discharge port to the air-oil separation chamber can also be prevented. Moreover, since the liquid discharge port is provided at the lowest portion between the largest-diameter portion of the liquid discharge chamber and the air-oil separation plate, liquid adhering to the interior wall of the air-oil separation chamber and the liquid discharge chamber can be guided into the liquid discharge port by gravity for smooth discharge therefrom. Thus, since the separated liquid can be discharged smoothly even when the centrifugal air-oil separator is disposed horizontally, the degree of freedom in the layout of the centrifugal air-oil separator can largely be enhanced.
According to a second aspect of the invention, there is provided a centrifugal air-oil separator as set forth in the first aspect of the invention, wherein a reverse flow prevention wall is provided above the liquid discharge port.
According to the construction, since the reverse flow prevention wall is provided above the liquid discharge port, the reverse flow of liquid from the liquid discharge port to the liquid discharge chamber can effectively be prevented.
According to a third aspect of the invention, there is provided a centrifugal air-oil separator as set forth in the second aspect of the invention, wherein the reverse flow prevention wall is provided at a lower portion within the liquid discharge chamber in such a manner as to follow a swirl flow to connect to an interior wall of the liquid discharge chamber on a more upstream side of the swirl flow than the liquid discharge port.
According to the construction, since the reverse flow prevention wall is formed at the lower portion within the liquid discharge chamber in such a manner as to follow the swirl flow, the influence imposed on the swirl flow by the reverse flow prevention wall can be restrained to a minimum level. In addition, since the reverse flow prevention wall connects to the interior wall of the liquid discharge chamber on the more upstream side of the swirl flow than the liquid discharge port, the generation of negative pressure that would draw liquid out of the liquid discharge port can be prevented by avoiding the direct action of the swirl flow on the liquid discharge port.
According to a fourth aspect of the invention, there is provided centrifugal air-oil separator as set forth in the third aspect of the invention, wherein a liquid discharge passage is provided on a more downstream side of the swirl flow than the liquid discharge port between the interior wall of the liquid discharge chamber and the reverse flow prevention wall.
According to the construction, since the liquid discharge port is provided on the more downstream side of the swirl flow than the liquid discharge port and between the interior wall of the liquid discharge chamber and the reverse flow prevention wall, the liquid adhering to the interior wall of the air-oil separation chamber and the liquid discharge chamber can be guided into the liquid discharge port without any problem.
According to a fifth aspect of the invention, there is provided a centrifugal air-oil separator as set forth in the first aspect of the invention, wherein the reverse flow prevention wall is formed integrally with the liquid discharge chamber in such a manner as to extend from the liquid discharge chamber substantially in parallel with an axis of the air-oil separation chamber.
According to the construction, since the reverse flow prevention wall formed integrally with the liquid discharge chamber extends from the liquid discharge chamber substantially in parallel with the axis of the air-oil separation chamber, the reverse flow prevention wall can be formed without increasing the number of components. Moreover, since the reverse flow prevention wall can be formed at the same time as the air-oil separation chamber and the liquid discharge chamber are formed, the formation of the reverse flow prevention wall can be facilitated.